The lymphocyte transformation test and the macrophage migration inhibition test are quantitative methods invaluable for examination of beryllium (hereafter referred to as Be) effects on cell-mediated immunity. We recognized that the Be sensitizing ability was related to active as well as passive cell-mediated immunity in mice subcutaneously injected with Be once a week over a 6-week period. Be also affects B cells, and it increases the amount of immunoglobulins in sera. In the study of immunological health surveys of Be workers in a copper-beryllium casting factory, the serum complement titer tended to be lower in Be workers than in the controls. In mice, injected with Be once a week over a 12-week period, serum complement titers decreased. Correlation coefficients of the experimental parameters showed a significant negative correlation between the complement titers and the prothrombin time or the coagulation time for factor VII, using mice injected with 5 micrograms of Be. It was suggested that increases in the complement titers after Be administration may be induced by temporarily-activated plasma serin protease, which is a component of blood coagulation factor VII. The delta-aminolevulinic acid dehydratase and porphobilinogen deaminase activities were significantly elevated in the pregnant untreated group, compared with the nonpregnant mice (the control group). However, it was noted that these values in the pregnant mice injected with 50 micrograms of Be were almost the same as the values of the controls. It suggests that Be suppressed the expected pregnancy-induced increase in hematopoietic function. There are at least two risk factors induced in the effects of beryllium on organisms-exposure to the metal and inheritance of the genetic marker. It is necessary to reduce exposure, to give preventive education and to carry out periodic health examinations for the prevention of disease induced by Be.